Combine bill and invoice in a single transaction

I would like to combine some bills (that I need to pay) and some invoices (that I’m being payed) into a single transaction so that it is correct with my bank statement. Is this possible?

I work as an independent contractor, and the billing(?) company that pays me sends me a bill for their services, and then subtracts that bill from what they pay me so the actual transfer is the net transfer.

Example situation

I send them two invoices for 800 and 400 euro, and they send me bills for 100 and 50 euro.
I entered all four into GnuCash as separate items (since they are).

Upon payment there is one transfer of 1050 euro to my bank account.

Current situation

I currently have combined the two invoices with the transaction, but now the second one is marked as unpaid (due to partial payment). I looks something like this:

Desired situation

The statement would look something like this:

How do I combine these bills and invoices so that the transaction is correct with the transfer to my bank account, and all bills/invoices are marked as payed?

(Apologies for any incorrect terms, I’m translating from Dutch)